More than a third of Plymouth's special police officers will be on patrol this weekend in the city.

A spokesperson said no trouble was anticipated but officers wanted to reassure people and traders they would "robustly deal" with trouble-makers.

The specials will be in addition to officers and PCSOs on patrol in Plymouth, after riots in other cities.

Plymouth has about 110 police specials, with 42 patrolling this weekend, a spokesperson said.

Deputy chief officer for the special constabulary Richard Clatworthy said: "The continued response has been overwhelming with special constables volunteering a phenomenal number of hours at short notice."

'Words of advice'

A police spokesperson said: "The aim of these highly-visible patrols is to reassure residents and traders who have seen events nationally and are anxious about any potential outbreaks of disorder in their communities."

About 80 officers from Devon and Cornwall are also helping the Metropolitan Police and Avon & Somerset and Gloucestershire forces keep order after rioting in London, Bristol and Gloucester.

Devon and Cornwall Police said they were continuing to monitor social media sites and take action where appropriate.

A spokesperson said a 20-year-old man from Torquay, three men in their twenties from Newquay and an 11-year-old girl in Plymouth had received visits from police.

The spokesperson said officers had given "words of advice concerning entries on to social networking sites".